You select portions that correspond each to one oscillation in the WAV file. They do not necessarily have 32 samples in the WAV, and unless the instrument has an appropriate sample rate, the oscillations would not span across 16 ms either; however, for best results the selections must be "evenly spaced" so that their phases do not alter across the final waveform. You have to control the N163 wave sequence separately to play through all the samples at an appropriate rate that resembles the original instrument, and this depends on how far apart the selected oscillations are, so a plain sequence like {0 1 2 3 4 ...} may sound too fast or too slow for most pitches. (For instance, for each octave raise the wave sequence has to become twice as fast.)